1. Field of the Invention
The present invention relates in general to a method of preventing reduction of sales amount of records due to a digital music file illegally distributed through a communication network, and more particularly to a method which allows sharing and distributing of a digital music file employing a security technique, such that it can restrain a user from holding and using a digital music file illegally reproduced and thus prevent the reduction of sales amount of records due to the digital music file illegally distributed through a communication network.
2. Description of the Prior Art
Generally, a record corporation cells a record produced by recording an analog or digital signal on a medium such as a cassette tape or an optical disc(e.g. long play disc or compact disc).
As digital audio-concerned techniques have been developed, many software and hardware devices have been developed for forming an analog or digital signal recorded onto a medium as a digital-format music file such that it can be stored or copied easily with a digital device(e.g. personal computer terminal), and freely reproduced from the device.
The digital-format music file generated by the software or hardware devices is easily propagated through a communication network due to its characteristic of simplicity in reproducing and transmitting. Especially, a digital music file with MP3(MPEG1 layer 3) format, which recently has gained great popularity, has a data size smaller than that of a conventional digital music file by 90 to 92%, while its sound quality is as high as an original sound recorded in the medium(for example, compact disc) by using an audio compression technique of MPEG 1. For this reason, a large quantity of digital music files with MP3 format have been illegally reproduced through the communication network.
Moreover, many programs or services such as “Napster” or “Soribada” for sharing digital music files with data format such as MP3 between different users using a P2P(peer to peer) method have been proposed and popularized among users recently. Thus, a search and reproduction of the digital music file through the communication network are gradually becoming easier and more simplified, and thus the users of the programs or the services are progressively increased in number.
Consequently, the conventional digital music file is disadvantageous in that reproduction of the digital music file infringes illegally a copyright of the music and causes sales amount of records to be reduced.